1. Field of the Invention
The present invention relates to an administration method of anticancer drugs.
2. Description of the Related Art
Substantially all living things on earth exhibit one common cyclicalbiological rhythm, known as a ‘circadian rhythm,’ with a period of 24 hours in order to adapt themselves to a change of day and night resulting from the rotation of the earth. More particularly, such a circadian rhythm involves a behavioral rhythm of being active during the daytime while sleeping at night, a physiological rhythm including, for example, hormone secretion with repeated rises and falls over a period of one day, variation of body temperature, expression of genes, etc., and the like, which are substantially observed in most of all life forms. A molecular system to form the circadian rhythm in the body is referred to as the ‘circadian clock.’
The circadian rhythm is closely associated with the health of a living thing. Loss of the circadian rhythm occurring due to a malfunction of a normal circadian clock may cause a metabolic disease such as diabetes or hypertension and, occasionally, a serious disease such as cancer.
The smallest unit of configuring the human body is referred to as a ‘cell.’ The cell normally divides, grows and/or dies and is eliminated by internal control of the cell, thus balancing the number of cells. In case of damaging a cell due to any cause, the cell may be restored by some healing process and function again as a normal cell. On the other hand, the cell occasionally undergoes apoptosis if it could not be restored. However, when there is a variation in genes of cells owing to different reasons, some cells may be abnormally altered and show incomplete maturation and excess proliferation, and this may be defined by the term ‘cancer.’
Further, cancer invades into surrounding tissues and organs and destroys the same, and is characterized by being transferred to other organs (‘cancer metastasis’). Cancer may refer to cell proliferation which is out of control, and which destroys the structure and functions of normal cells and organs. Accordingly, it cannot be emphasized enough that diagnosis and treatment of cancers are very important.
Cancer treatment is generally classified into three kinds of treatment methods, that is, surgical treatment, anticancer chemotherapy, and radiation treatment. Further, local treatment, hormone therapy, photodynamic therapy, laser treatment, or the like have been also used. In recent years, even immunotherapy and gene therapy have been included. The surgical treatment may include, for example, radical surgery for attaining desired treatment effects, prophylactic surgery for obtaining protective effects, and palliative surgery for alleviating symptoms of the disease. Alternatively, the anticancer chemotherapy is a treatment method of using specific medicines to kill cancer cells, that is, anticancer drugs to cure the cancer, which is a systemic treatment method to be effective to cancer cells having spread through the whole body. Further, the radiation treatment is a treatment method of directly attacking a cancer mass in order to kill cancer cells.
With regard to the treatment of cancers, the anticancer chemotherapy is usually adopted as an optimal treatment method in clinical fields. The anticancer drugs may include, for example, cell-cycle-specific drugs acting on cells only at a specific period of time in a cell cycle (ex., acting on M or S phase) and cell-cycle-nonspecific drugs acting on any cells under proliferation regardless of the cell cycle. In general, these anticancer drugs inhibit a synthetic process and mitotic division of DNA and RNA or, otherwise, produce harmful effects upon DNA molecules themselves, thus killing the cancer cells. However, although the anticancer chemotherapy attains effects of extending the lifetime of a cancer patient, this seriously affects some of normal cells having active cell division and proliferation, such as mucosa in the gastrointestinal track, hair, bone marrow, cells in a genital organ system, etc. as well as the cancer cells. In fact, after the anticancer chemotherapy is executed, the patient may suffer from anemia, reduction in numbers of white blood cells and/or blood platelets, cold sores in the mouth, and nausea, vomiting, diarrhea, or the like, and other serious side effects such as hair loss, reproductive dysfunction, etc. may also be caused.
In recent years, some scientists have proposed that the important factor affecting the survival of cancer patients is not the anticancer chemotherapy itself but a timing of applying the therapy to the patient, which would be a solution for considerably decreasing damage of DNA in normal cells. However, since a scientific background to support the above proposal is not sufficient, it is difficult to adopt this theoretical proposal in clinical fields.
Michele A. Gauger, Aziz Sancar. Cryptochrome, Circadian Cycle, Cell Cycle Checkpoints, and Cancer. Cancer Res 2005; 65:6828-34, have described that collapse of a circadian clock caused by DNA damage may influence a cell reaction and such influences may depend upon a mechanism of collapse of a bio-cycle.